At temperatures of approx. 375 degrees Celsius and a pressure 220 times higher than normal, water reaches the supercritical state, where the liquid and the gaseous phases can no longer be clearly distinguished – according to traditional text-book opinion.
“Arguments that the supercritical state might be subdivided into a gas-like and a liquid-like regime, separated by the so-called Widom line, haven’t been put forward until a few years ago,” explains Christoph Schran from the Center for Theoretical Chemistry at the Ruhr-Universität Bochum, headed by Prof Dr Dominik Marx.